16alpha-methyl-6alpha-fluoro derivatives of reichstein substance s



United States "Patent Cffice 3,538,131 Patented Nov. 3, 1970 3,538,131lfia-METHYL-fiea-FLUORO DERIVATIVES OF REICHSTEIN SUBSTANCE S Howard J,Ringold, Carl Djerassi, and John Edwards,

(fHzOR ICO In-OH Mexico City, Mexico, assignors, by mesne assignments, 5-CHa CH1 to Syntex Corporation, a corporation of Panama No Drawing.Filed Jan. 27, 1959, Ser. No. 789,242 Claims priority, applicationMexico, July 9, 1958,

51,522; Sept. 6, 1958, 52,051; Sept. 24, 1958, 52,202; Dec. 11, 1958,53,047 and Int. (:1. C07C 169/32 10 0 US. Cl. 260-397.47 8 Claims Thepresent invention relates to novel cyclopentanophenanthrene compounds.

More particularly the present invention relates to novel6a-fluoro-16m-methyl derivatives of cortisone, hydrocorti- I h b 1 some,prednisone and prednisolone including derivatives n t e a We formu as Xrepresents =0 or further substituted by 9u-chloro, fluoro or bromo aswell as 21-mono esters of these compounds. All of the foregoingcompounds are active cortical hormones having marked anti-inflammatoryactivity. The present inven- 011 tion also relates to certain novelintermediates for the production of these compounds and especially16a-meth- H yl-6a-fluoro derivatives of substance S.

The novel cortical hormones and intermediates of the 25 presentinvention are illustrated in part by the following formulas: Yrepresents hydrogen, fiuoro, chloro or bromo and R OHgOR CHzORrepresents hydrogen or a hydrocarbon carboxylic acyl group of less than12 carbon atoms, including saturated OH U OH 30 or unsaturated, straightor branched chain aliphatic, cyclic CH or cyclic-aliphatic which may beconventionally substi- 3 X ---CHa I Y Y tuted w1th hydroxyl or halogenfor example. Examples of such acyl groups are acetate, propionate,t-butyrate, l hemisuccinate, enanthate, caproate, benzoate, trimethyllacetate, phenoxyacetate, phenylpropionate, cyclopentyl- 0 propionate andfl-chloropropionate.

V The novel compounds above set forth are prepared by F F a processillustrated in part by the following equation:

OHzOH '1 CHzOH j i I --.OH ---OH ethyleneglywl I Y then peracid I Yboron l trifiuoride CH2OH CHzOH t I P ...OH ".011 HO/\ ---oH, lithium o=--CH:

Y aluminum hydroxide Y o i o l on F on F esterlfication then dry HClCHzOR sodium borohydride then pyruvic acid and acetic acid NHz dioxide(III-120R CO In the above equations X, Y and R represent the same groupsas heretofore set forth.

In practicing the process above outlined, the starting material namely16a-methyl-cortisone or derivatives thereof having a 9oc-Ch1OI0, brornoor fluoro group prepared as set forth in US. application of Djerassi andRingold, Ser. No. 789,248 filed as of even date herewith, now abandonedis treated with a lower alkyleneglycol such as ethylene glycol in anorganic solvent as for example benzene and in the presence ofp-toluenesulfonic acid to form the corresponding3,20-bis-cycloalkyleneketal such as the 3,20-bis-cycloethyleneketal. Thedouble bond which migrated to the C-5 (6) position was then epoxidizedby reaction with a peracid to form the illustrated3,ZO-bis-cycloethyleneketal of16oc-II1ethy1-5a,6ocoXido-pregnan-l7a,2l-diol-ll-one or the 9ot-haloderivasomicarbazide acetate OHs tives. Treatment of these last compoundswith boron trifluoride etherate in ether-benzene gave the correspondingSa-hYdIOXY-Gfl-flllOfO-l1-k6t0 compounds. Reduction of the ll-keto groupwith lithium aluminum hydride gave the corresponding llfl-hydroxyderivatives and conventional esterification at C21 of either the ll-ketoor 11 B-hydroxy compounds followed by vigorous acid treatment gave thecorresponding 6u-fluoro compounds including the reconstituted 3 and 20keto groups. Preferably the vigorous acid treatment was with a stream ofdry hydrogen chloride introduced into a glacial acetic acid solution ofthe compounds at about 15 C. In this way there was formed the 21-esterspreferably the acetates of l6a-methyl-6a-fluoro-cortisone, the indicated9u-halo derivatives thereof and of 16a-methyl-6a-fluoro-hydrocortisoneand its indicated 9a-halo derivatives. These esters were hydrolyzed tothe free alcohols by conventional mild alkali treatment and 21-esterswere prepared by conventional treatment of the free compounds with acidanhydrides or chlorides of hydrocarbon carboxylic acids of up to 12carbon atoms.

As illustrated above a modification involved the reaction of the free160c-1I16thY1-6ot-flHOIO-COItiSOIlG with semicarbazide acetate to formthe 3,20 bis-semicarbazone derivatives thereof, the treatment of thesemicarbazone with sodium borohydride to reduce the ll-keto group to thellfl-hydroxy group and treatment with pyruvic acid in admixture withacetic acid and then acetic anhydride to form the 21-acetate of16oc-II16thYl-6oz-fill0r0- hydrocortisone. By conventional hydrolysisthe acetate was converted to the free compound and by conventionalesterification the 21-esters thereof were prepared.

The A compounds thus prepared were as indicated transformed into thecorresponding A -derivatives by the treatment thereof with seleniumdioxide, preferably by refluxing in t-butanol in the presence ofpyridine. Although the free compounds may be used in this reaction the21-esters are preferably used and the 21-esters of the A -derivativesthereafter conventionally hydrolyzed to form the free alcohols. Othermethods such as the known incubation with corynebacterium simplex mayalso be used for the conversion of the A -compounds to corresponding A-derivatives.

Another method for the preparation of the ZI-acetate In the aboveequation Ac represents acetate and R of 16a-methyl-6a-fluoro-cortisoneis illustrated by the represents hydrogen or acetate. followingequation:

CH3 (EH3 t o T011. -Ai 1. peraoid HO HO 2 boron trifluoride (IJHB (3H3 E1.011 /\i 1.0m introduction 0f17vz-OH HO- HO- (5R1 F 6H F 21-acetoxyintroduction HzOAc H,,

"0H 0 /\|i FU CH3 a R1\F 0R1 F l oxidation l fige gl 1or ({lHzOAc (3H3CO CO aqueous or dry HCI 1-acetoxy introduction In practicing theprocess above set forth 16a-methyl- A -pregnen-3/3-o1-11,20-dione whichhas been prepared as set forth in the application of Djerassi andRingold, Ser. No. 789,243, filed as of even date herewith, now abandonedwas epoxidized by reaction with a peracid such I as perbenoic orpermonophthalic to form l6a-methyl-5a, 6u-oxido-pregnan-3B-ol-l1,20dione. Treatment of this compound with boron trifiuoride preferably inthe form of its etherate and in mixture with ether and benzene produced16a methyl 6 3-fluoro-pregnan-3fi,5a-diol-l1, 20-dione. The 17u-hydroxygroup was then introduced in a conventional way i.e., the last mentionedcompound was heated with acetic anhydride in the presence ofp-toluenesulfonic acid to form 16-methyl-6fi-fluoro-A -pregnen-3,B,5oc,20 triol ll-one triacetate; the double bond was epoxidized byreaction with a peracid and the resulting 16a methyl 65 fluoro 17a,20oxido pregnan- 3,8,5oz,20-t1i0l11-0116 triacetate was subjected toalkaline treatment. Under mild conditions such as 1% methanolicpotassium hydroxide solution at room temperature 16w methyl-66-fluoro-pregnan-3fl,5a,17a triol-1l,20-dione 5- acetate was formed,stronger conditions such as refluxing for 4 hours gave the correspondingfree compound.

For the introduction of the 21-acetoxy group the compounds justdescribed' were transformed into their 21-iodo derivatives, eitherdirectly by reaction with iodine and calcium oxide in admixture withtetrahydrofurane and methanol or indirectly by C-21 monobrominationfollowed by reaction of the 21-bromo compound with sodium iodid'e. Theresulting compounds l6a-methyl-6 3-fluoro-Zl-iodo-pregnan-3flfiu,17a-triol-11,20-dione or the S-acetatethereof were then reacted with potassium acetate in acetone to preparethe corresponding 21-acetoxy derivatives.

Oxidation of the 3/3-hydroxy group of these compounds with chromic acidgave l6a-methyl-6/3-fluoro-pregnan-5a, l7a,2l-triol-3,l1,20-trione2l-acetate or 5,2l-diacetate and treatment of these compounds with smallamounts of aqueous concentrated hydrochloric acid in acetic acidsolution gave 16-methyl-6,8-fiuoro-cortisone 2l-acetate. Treatment ofthis compound with dry hydrogen chloride in glacial acetic acid invertedthe steric configuration at C-6 and gave the previously described16OL-l'l'l6thyl-60tfluoro-cortisone 2l-acetate. Instead of the last twosteps the one step treatment of the 5a-hydroxy 6B-fluoro compounds withdry hydrogen chloride in glacial acetic acid gave both inversion anddehydration.

Instead of subjecting 16u-methyl-6fl-fluoro-pregnan-35,:,17oc-t1i0l-1L20-di0116 (or its S-acetate) to the steps ofacetoxylation at C-Zl, oxidation at C-3, dehydration at C-5 andinversion at C6, the sequence of these operations can be altered: the3,8-hydroxyl group can first be oxidized with chromic acid to producel6ot-methyl-6,8- fluOrO-pregnan-Sa,17u-diol-3,11,20-trione the abovecompounds were then dehydrated by reaction with aqueous concentratedhydrochloric acid to form 16a-methyl-6B- fluoro-2l-desoxy-cortisone, thesteric configuration at C-6 was then inverted by the treatment with dryhydrogen chloride; either before or after this inversion, 16a-methyl-6a-fluoro-2l-desoxy-cortisone was acetoxylated by known methods.

The production of novel intermediates for the production of the corticalhormones of the present invention is illustrated in the followingequation:

l boron trifluorido poracid $1M I a 17a-hydroxy introduction 21-acetoxyintroduction CHzOAc I l oxidation HO 5 E DAe F iQF ldry H01 CHzOAc Inthe above equation Ac represents acetate.

In practicing the process above outlined the starting material was theknown 16u-methyl-A -pregnen-35-01-20- one acetate. Its double bond wasepoxidized by reaction with a peracid, such as monoperphthalic acid orperbenzoic acid, and thus there was obtained 16oc-1'116thyl5oc,6aoxido-pregnan-3fi-ol-ZO-one acetate; the latter was treated with borontrifiuoride etherate in mixture with ether and benzene, following themethod described in US. application Ser. No. 753,629, filed Aug. 7,1958. There was thus produced 16a-methyl-6p-fluoro-pregnan-3,8,5a-di01--one 3-acetate. A hydroxyl grou was introduced at C-17a of this compoundby the method of Gallagher and Kritchevsky (J. Am. Chem. Soc., 73, 184(1951)) i.e. by slow distillation of a solution of the compound inacetic anhydride, in the presence of p-toluenesulfonic acid, there wasobtained 16a-methyl-6/8-fiuoro-A -pregnan-3,8,5u, 20-triol triacetate;this was epoxidized to 16a-methyl-6B-fluoro-17,20-oxido-pregnan-3B,5a,20-triol triacetate by reaction with aperacid; the latter was then converted by alkaline treatment into16a-methyl-6fl-fiuoro-pregnan-3p, 5a,17a-triol-20-one S-acetate.

The above compound was monobrominated at C21, preferably in dioxanesolution; the bromine atom was substituted for iodine by treatment withsodium iodide in ethanol solution and the resulting16a-methyl-6fl-fiuoro- 21-iodo-pregnan-3B,5a,17a-triol-2O one 5 acetatewas acetoxylated to produce 16a-methyl-6,8-fluoro-pregnan-3B,5a,17ot,21t6t1"0l20-0116 5,21-diacetate by refluxing with potassiumacetate in mixture with acetone. The 3,6-hydroxyl group was oxidized tothe keto group, preferably by reaction of an acetone solution of thesteroid with an 8N solution of chromic acid in dilute sulfuric acid, atlow temperature and under an atmosphere of nitrogen; there was thusobtained 16a-methyl-6,8-fluoro-pregnan-5a,17a, 21-triol-3,20-dione5,21-diacetate. Upon treatment with dry hydrogen chloride in glacialacetic acid solution, there was converted the 3-keto-5a-acetoxy groupinginto the A -3-keto grouping and the steric configuration at C-6 wasinverted to produce the desired 16a-methyl-6wfiuoro- A-pregnen-17a,21-dio1-3,20-dione 21-acetate.

Obviously, the order of the above reactions can be modified to firstoxidize the 3fi-hydroxyl group of 1604-methyl-6fl-fluoro-pregnan-3fi,5a,17a-triol-20-one 5 acetate to the ketogroup by means of the reaction with 8N chromic acid, then there wasproduced 16ot-methyl-6afluoro-M-pregnen-17a-ol-3,20-dione by thereaction with dry hydrogen chloride and the acetoxyl group at C-21 wasintroduced, in this case preferably by monoiodination at C-21 withiodine and calcium oxide followed by acetolysis with potassium acetatein mixture with acetone.

The various steps above set forth may be performed with other reagents.For example, the double bond of the starting compound can be epoxidizedeither with perbenzoic acid in chloroform solution or withpermonophthalic acid in ether-chloroform solution, and the latterreagent can be employed for the epoxidation at C-17,20 instead of theaforementioned reaction with perbenzoic -CHa acid in benzene solution;the bromination at 0-21 can be effected either in chloroform solution orin a mixture of chloroform and acetic acid; the treatment with dryhydrogen chloride can be substituted by treatment with any other acidsufiiciently strong to cause the inversion of the steric configurationat C-6 and the elimination of the elements of acetic acid, such as forexample with hydrogen fluoride; the method mentioned of monoiodinationat C 21 followed by acetolysis can also be used for the C21-acetoxylation of16a-methyl-6,8-fluoro-5a-acetoxy-pregnan-35,17a-diol-20-one, or the21-bromo compound can be converted into the 21-acetoxy compound withoutisolating the intermediate 21-iodo compound.

The method above set forth is also suitable for the prep aration of theimportant pregestational hormone16amethyl-6a-fluoro-17ot-acetoxy-progesterone. For preparing thiscompound it is necessary to esterify the two hydroxyl groups of16ot-methyh6fi-fluoro-pregnan-3B,5a,l7a-triol- 20-one S-acetate. Theacetate group at C-3 of the resulting 3,5,17-triacetate is selectivelyhydrolyzed to obtain 16a-methyl-65-fluoro-pregnan-35,5a,17a triol 2O one5,17-diacetate. The subsequent oxidation of the Sfl-hydroxyl group to aketo group, followed by the treatment with dry hydrogen chloride inglacial acetic acid gives 16ot-methyl-6a-fluoro 17oz acetoxyprogesterone. If the compound is further acetoxylated at C-21 by theafore mentioned method, the final product obtained is16mmethyl-6afluoro-A -pregnen-17a,21-diol-3,20-dione 17,21- diacetate.Instead of introducing an acetate group at C- 17, there can beintroduced the residue of any other hydrocarbon carboxylic acid of up to12 carbon atoms.

It may be noted further that the final product of the process above setforth namely 16a-methyl-6a-fiuoro-A pregnen-17a,21-diol-3,20=dione21-acetate upon conventional hydrolysis with alkali gave the freecompound and conventional esterification of this free compound with acidanhydrides or chlorides of hydrocarbon carboxylic acids of less than 12carbon atoms gave the corresponding 21-monoesters.

The conversion of 16a-methyl-6a-fluoro-A -pregnen-17a,21-diol-3,20-dione into previously referred to cortical hormones isillustrated by the following equation:

l dehydration l dehydration ("JHzOAc CHzOAc (I) O C O In the aboveequation R, Y and Ac represent the same groups as heretofore set forth.

As indicated above the starting material is 16u-methyl- 6a-fluoro-A-pregnen-17a,21-dio1-3,20 dione or the hydrocarbon carboxylic acidesters thereof of less than 12 carbon atoms. It may be noted that thestarting material may first be converted into the correspondingl-dehydro compounds and that thereafter the various steps are performedupon either the A -3-ketones or the corresponding A -3-ketones. Wherethis conversion is performed by refluxing the starting compound withselenium dioxide in the presence of t-butanol and catalytic amounts ofpyridine preferably a lower fatty acid ester of 160t-m6thy1-6OL-fluoro-A -pregnen-l7a,2l-diol-3,20-dione is used for higher yields.Where this additional double bond is introduced by biochemical methodssuch as incubation with corynebacterium simplex ATCC-6946 preferably thefree compound is used. The next step for either the A -compounds or theA -compounds involves as indicated above the introduction of thell-hydroxy group and for this step preferably the free compounds arealso used. Incubation of the starting free compounds,16a-methyl-6a-fluoro-A pregnen-17a,21-diol 3,20-dione or16a-methyl-6a-fluoro- A -pregnadien-17u,21-diol-3,20-dione with adrenalgland material or with the fungus Cunninghamella baz'nier ATCC9244 gavethe corresponding 11,8-hydroxy derivatives, i.e.,16a-methyl-6a-fluoro-hydrocortisone or160tmethyl-6ot-fluoro-prednisolone. By conventional esterification ofthese compounds there was produced the 21- monoesters thereof ofhydrocarbon carboxylic acids of less than 12 carbon atoms. Byconventional oxidation of these compounds with chromic acid there wasalso pro- 12. duced 16a-methyl-6ot-fluoro-cortisone and16a-methyl-6otfluoro-prednisone as well as the 2l-mono esters thereof ofhydrocarbon carboxylic acids of less than 12 carbon atoms.

The biochemical oxygenation of 160t-l11BthY1-6OL-fill0l0- A-pregnen-l7u,2l-diol-3,20-dione or its l-dehydroderivative with Rhizopusnigricans ATCC 6227b gave 16a-methyl6a-fluoro-epi-hydrocortisone and16u-methyl-6ot-fluoroepi-cortisone i.e. the llot-hydroxy derivatives ofthe starting compounds. For the next step indicated in the equationeither the 116- or lla-hydroxy compounds were conventionally esterifiedat C-2l preferably to form the lower fatty acid esters such as theacetate indicated, and the acetates were heated with methanesulfonylchloride in admixture with pyridine and dimethylformamide to form 160amethyl 60 fluoro-A -pregnadien-l7u,2l-diol- 3,20-dione 2l-acetate or16Ot-l'l16thY1-6OC-flll0f0-A pregnatrien-l7et,21-diol-3,20-dione2l-acetate.

To these compounds there was then applied the method which Fried et al.(J.A.C.S. 79, 1130 (1957)) described for the introduction of halogen atC-9 of the cortical hormones. Thus by reaction with hypobromous acidthere was obtained 16a-methyl-6a-fluoro-9a-bromohydrocortisone acetateand 16u-methyl-6a-fluoro-9a-bromoprednisolone acetate, thesebromohydrins were converted into 160;-methyl-6a-fluoro-9ot,1lfl-oxido-Mpregnen (and A-pregnadien)-l7ot,2l-diol-3,20-dione 2l-acetate by reaction withpotassium acetate in ethanol and the epoxide rings were opened withhydrogen chloride or hydrogen fluoride to form the 21-acetates of16-methyl-6a-fluoro-9a-chlorohydrocortisone, 16methyl-6u-fluoro-9ot-chloro-prednisolone, l6 methyl 60,9oz difluorohydrocortisone and 16 methyl 6a,9a difluoro prednisolone respectively.Here again conventional oxidation with chromic acid for example producedthe corresponding 11-keto-2l-acetates and conventional hydrolysis as forexample with dilute methanolic potassium hydroxide or sodium methoxideproduced the corresponding free alcohols which upon conventionalesterification gave other esters of hydrocarbon carboxylic acids of lessthan 12 carbon atoms. Obviously the above described method may beconventionally modified. Thus the hydrocortisone or cortisonederivatives may be dehydrogenated as a final step instead of initiallyto form prednisolone or prednisone derivatives. Further, the dehydrationbetween C-9 and C-ll is also effected by reaction with p-toluenesulfonicacid in benezene; for the reaction with hypobromous acid there may beemployed N-bromoacetamide together with perchloric acid, although therecan be used any other reagent capable of liberating hypobromous acid,such as any other N-bromo-amide or -imide or the hypobromite of analkali or alkali-earth metal; the reaction with the hydrogen halide canbe carried out in any solvent inert to this reaction such as methylenechloride or carbon tetrachloride.

The following specific examples serve to illustrate but are not intendedto limit the present invention.

EXAMPLE I A mixture of 5 g. of l6ot-methyl-cortisone, 150 cc. ofanhydrous benzene, 60 cc. of ethyleneglycol distilled over sodiumhydroxide and 800 g. of p-toluenesulfonic monohydrate acid was refluxedfor 12 hours with the use of an adapter for the continuous removal ofthe Water formed during the reaction. Aqueous sodium bicarbonatesolution was added to the cooled mixture and the organic phase wasseparated, washed with water, dried over anhydrous sodium sulfate andevaporated to dryness. The residue crystallized from acetone-hexane togive 1602-1116fhyl-3 ,20bis-ethylenedioxy-M-pregnen-17a,21-diol-1l-one.

4 g. of the above compound was dissolved in 80 cc. of chloroform, cooledto 0 C., mixed with an ether solution of monoperphthalic acid containing1.2 molar equivalents of the reagent and kept in the dark at atemperature between 0 and 5 C. for 16 hours. The mixture Was dilutedwith water and the organic layer was separated and washed with sodiumbicarbonate solution and water to neutral, dried over anhydrous sodiumsulfate and evaporated. Crystallization of the residue fromacetone-hexane yielded 16a-methyl-3,20-bis-ethylenedioxy 5 oc,6otoxidopregnan-17a,21-diol-1l-one.

To a solution of 3 g. of the above compound in 300 cc. of a mixture ofequal parts of ether and benzene there was added 3 cc. of borontrifluoride etherate and the mixture was kept at room temperature for 3hours and then diluted with water. The organic layer was separatedwashed with water, dried over anhydrous sodium sulfate and evaporated todryness. The residue was chromatographed on neutral alumina, thus giving16a-methyl-6B- fiuoro 3,20bis-ethylenedioxy-pregnan-5a,17a,21-triolll-one.

A mixture of 2 g. of the above compound, 15 cc. of pyridine and 6 cc. ofacetic anhydride was kept overnight at room temperature, poured into icewater, heated on the steam bath for half an hour and cooled. Theprecipitate was filtered, washed with water, dried and recrystallizedfrom acetone-hexane. There was thus obtained l6a-methyl 6Bfluoro-3,20-bis-ethylenedioxy-pregnan- 5a,l7u,21-triol-11-oneZl-acetate.

A slow stream of dry hydrogen chloride was introduced for 4 hours into asolution of 1.5 g. of the above compound in 100 cc. of acetic acid,maintaining the temperature below 15 C. After pouring into ice water theprecipitate was filtered and dried. Recrystallization fromacetone-hexane afforded 16u-methyl-6a-fiuoro-cortisone 21- acetate.

A mixture of 0.5 g. of the above compound, 25 cc. of t-butanol, 0.2 g.of selenium dioxide and 0.1 cc. of pyridine was refluxed under anatmosphere of nitrogen for 48 hours, filtered through celite and thefilter was washed with a little hot t butanol. The combined filtrate andwashings was evaporated to dryness under reduced pressure. The residuewas refluxed for 1 hour with decolorizing charcoal in acetone, filteredfrom the charcoal and the filtrate was evaporated to dryness.Chromatography of the residue on washed alumina yielded16a-methyl-6u-fluoroprednisone 2l-acetate.

A suspension of 1 g. of 16a-methy1-6a-fluoro-predisone 21-acetate in 10cc. of absolute methanol was treated with 10 cc. of a solution of sodiummethoxide in absolute methanol (prepared by dissolving 60 mg. ofsodium), with stirring, under an atmosphere of nitrogen, at C. for 1hour. After precipitating with saturated aqueous sodium chloridesolution containing a few drops of acetic acid, the product wasfiltered, and recrystallized from acetonehexane, thus affording the free16u-methyl-6afluoro-prednisone.

By the same conventional method of acetylation described previously,there was esterified the hydroxyl group at C-21 of this prednisone,using the anhydride of other hydrocarbon carboxylic acids having up to12 carbon atoms. For example, by reaction with propionic anhydride therewas obtained 16a-methyl-6a-fiuoro-prednisone 21-propionate. There wasalso prepared in this the cyclopentylpropionate and benzoate.

EXAMPLE II By the same method to that of the previous example, a16u-methy1-9u-halo (fluoro, chloro, bromo)-cortisone afforded the3,ZO-bis-cycloethyleneketal and then the corresponding epoxide, byreaction with boron trifluoride the latter was converted into thecorresponding 16u-methyl- 618-fluoro 9ahalo-3,20-"bis-ethylenedioxy-pregnan-a, 17a,21-triol-11-one; the latterwas acetylated at (3-21 and then treated with dry hydrogen chloride togive the respective 16u-methyl-9a-halo-6a-fluoro-cortisone 21 acetate,which was then dehydrogenated by the reaction with selenium dioxide toproduce the corresponding l6a-methyl-6a-fluoro-9ahalo-prednisone2l-acetate.

By treatment with sodium methoxide, as described in Example I, there washydrolyzed the 21-acetate of 16amethyl 60c fiuoro c halo-cortisone aswell as 1600- methyl-6a-fluoro 9a halo (bromo, chloro or fluoro)-prednisone, and then the hydroxyl group at C-21 was reesterified with aradical of a hydrocarbon carboxylic acid different from acetic acid. Thesame esters specifically mentioned in Example I were formed of the freecompounds just mentioned.

EXAMPLE III In some experiments there was used for the formation of the3,20-bis-ketal of the starting compound intsead of ethyleneglycol,propyleneglycol to produce the corresponding cyclic3,20-bis-alkyleneketal. Since the ketal groups are later hydrolyzed, thefinal result in this case was the same.

EXAMPLE 1V Using in the esterification of the hydroxyl group at C-Zl of16amethyl-6,8-fluoro-3,20-bis-alkylenedioxypregnan-5a,17a,2l-triol-1l-oneor of its 9a-halo-analog an anhydride different from acetic anhydride,there were obtained the corresponding 21-esters of such bis-ketal andthen of 6a-fiuoro-16a-methyl-cortisone, its 9a-haIo-analogs and of thel-dehydro derivatives of these A -compounds, in the form of theirrespective 2l-esters. Typical esters thus formed were the propionate,cyclopentylpropionate and benzoate.

EXAMPLE V 5 g. of16a-methyl-6p-fluoro-9a-chloro-3,ZO-bis-ethylenediOXy-pregnan-Sa,17a,21-triol-11one (Example II) was dissolved in 150 cc. of anhydrous tetrahydrofuraneand under mechanical stirring it was slowly added, with occasionalcooling, to a suspension of 1.5 g. of lithium aluminum hydride in cc. ofanhydrous tetrahydrofurane. The mixture was then refluxed 'for 4 hoursand the excess of hydride was decomposed by the addition of a few dropsof acetone; 15 cc. of a saturated aqueous solution of sodium sulfatewere added, followed by the addition of anhydrous sodium sulfate, thesolid precipitate was filtered and the solution was evaporated todryness. Recrystallization of the residue from acetone-hexane furnished16oz methyl-6fl-fluoro-9a-chloro-3,20-bis-ethylenedioxy-pregnan-5a,11;8,17a,2l-tetrol.

The product was then subjected to the series of reactions described inthe previous examples, to produce the 21-ester of 1604methyl-6a-fluoro-9a-chloro-hydrocortisone and of 16umethyl-6a-fluoro-9a-chloro-prednisolone as well as, by hydrolysis of theesterified groups of such compounds, the free alcohols which uponre-esterification gave the other 21-esters previously mentioned inExample I.

EXAMPLE VI 4 g. of 16a-methyl-6a-fluoro-cortisone was allowed to reactwith a mixture of 90 cc. of methanol, 2 g. of semicar-bazidehydrochloride and 1.5 g. of anhydrous sodium acetate, at roomtemperature for 72 hours. Ice cold saturated sodium chloride solutionwas added and the reaction product was extracted with ethyl acetate. Theextract was washed with aqueous sodium bicarbonate solution and water,dried over anhydrous sodium sulfate, mixed with a few drops of pyridineand evaporated to dryness under reduced pressure. The residue consistedof the 3,20-bis-semicarbazone of 16a-methyl-6a-fluorocortisone.

3.5 g. of the above bis-semicarbazone in 80 cc. of tetrahydrofurane wastreated with a solution of 1.75 g. of sodium borohydride in 40 cc. ofwater and the mixture was kept overnight at room temperature; anadditional gram of hydride was added in 5 cc. of water and the mixturewas refluxed for 1 hour and cooled; the excess of hydride was destroyedby the addition of acetic acid, a few drops of pyridine were added andthe tetrahydrofurane was removed by distillation. Water was added to thecooled mixture and the product was extracted with ethyl acetate, washedwith water, dried over anhydrous sodium sulfate and evaporated todryness under reduced pressure. Recrystallization of the residue fromaqueous methanol containing a few drops of pyridine yielded the3,20-bis-semicarbazone of 16a-methyl-6a-fluoro-hydrocortisone.

2 g. of the 3,20-bis-semicarbazone of16ot-methyl-6afiuoro-hydrocortisone was suspended in a hot mixture of 10cc. of acetic acid and 2.5 cc. of water, then treated with 1.75 cc. of50% pyruvic acid and the mixture was refluxed. The bis-semicarbazonedissolved after a short time and the refluxing was continued for minutesfurther. Under continuous heating there was then added 20 cc. of waterin the course of 10 minutes and the mixture was slowly cooled andfinally kept in the refrigerator for 2 hours. The precipitate wasfiltered, washed with water, dried, dissolved in 10 cc. of pyridine,treated with 2 cc. of acetic anhydride and kept overnight at roomtemperature, in order to complete the acetylation at C2l which occurredduring the hydrolysis of the semicarbazone. The product was worked up bydiluting with water, extraction with ethyl acetate and recrystallizationfrom acetone-hexane of the residue obtained after the extract was washedand dried. There was thus obtained 16a-methyl-6ot-fluoro-hydrocortisone21-acetate.

Upon subsequent dehydrogenation, in accordance with Example II, therewas obtained 16a-methyl-6a-flu0roprednisolone 21-acetate.

Treatment with sodium methoxide in accordance with the method describedin Example I, afforded the free 16rx-methyl-6a-fluoro-hydrocortisone and16a-methyl6ufluoro-prednisolone. Esterification of the last compoundwith propionic anhydride produced after isolation and purification 16oz,methyl-6a-fiuoro-prednisolone-2l-propionate.

EXAMPLE VII A solution of 10 g. of 16a-methyl-A -pregnen-3,B-ol-11,20-dione in 200 cc. of chloroform was treated with an ether solutionof permonophthalic acid containing 1.2 molar equivalents of reagent, themixture was kept for 20 hours at room temperature and in the dark andthen diluted with water; the organic layer was separated, washed withwater, sodium bicarbonate solution and again with water until neutral,dried over anhydrous sodium sulfate and evaporated to dryness underreduced pressure. Chromatography of the residue on neutral alumina.yielded 16a-methyl-5a,6ot-oxido-pregnan-3,8-01- 11,20-dione.

A solution of 8 g. of the above compound in 800 cc. of a mixture ofequal parts of ether and benzene was treated with 8 cc. of borontrifluoride etherate and the mixture was allowed to react at roomtemperature for 3 hours. The solution was then washed with water, driedover anhydrous sodium sulfate and the solvent was evaporated. Theresidue was chromatographed on neutral alumina, thus furnishing1Got-methyl-ofl-fluoro-pregnan- 3B,5a-diol-11,20-dione.

A mixture of 6 g. of the above compound, 2.7 g. of p-toluenesulfonicacid and 300 cc. of acetic anhydride was subjected to a slowdistillation so 240 cc. of distillate was collected in the course of 5hours. The cooled residue was poured into ice water, the product wasextracted with ether and the extract was washed with 5% aqueous sodiumcarbonate solution and water, dried over anhydrous sodium sulfate andevaporated to dryness. The residue consisted of 16a-methyl-6B-fluoro-A-pregnen-3,:!,5et,20-triol-1l-one triacetate which was used for the nextstep without further purification. A pure sample of this compound wasobtained by chromatography on neutral alumina.

Alternatively, the above enol acetate was also produced by reaction withisopropenyl acetate, under the usual conditions for this reaction.

A mixture of 6 g. of the crude l6a-methyl-6fi-fluoro- 16 A-pregnen-3fl,5a,20-triol-ll-one and 240 cc. of a benzene solution ofperbenzoic acid containing 1.2 molar equivalents of the peracid was keptfor 20 hours at room temperature in the dark (in another experimentchloroform was used instead of benzene). The mixture was diluted withwater and the organic layer was washed With aqueous sodium bicarbonatesolution and water, dried over anhydrous sodium sulfate and evaporatedto dryness. The residue consisted of the crude 16a-methyl-6fl-fluoro-17a,20-oxidopregnan-3fl,504,20 triol 11 one triacetate. Apure sample of the compound was obtained by crystallization fromacetone-hexane.

The above crude oxido compound was treated with 500 cc. of a 1% solutionof potassium hydroxide in methanol for 1 hour at room temperature; themixture was neutralized with acetic acid, concentrated to a small volumeunder reduced pressure, diluted with water and the precipitate formedwas collected by filtration, washed with water, dried and recrystallizedfrom acetone-hexane. There was thus obtained16a-methyl-6fl-fluoro-pregnan- 3fi,5a,17a-triol-11,20=dione S-acetate.

A solution of 3 g. of the above compound in 150 cc. of dioxane wastreated with a solution of 1.2 g. of bromine in 70 cc. of dioxane (inanother experiment the dioxane was substituted for chloroform). Thebromine solution was added dropwise, with stirring and maintaining thetemperature at around 15 C. The mixture was kept at room temperature forhalf an hour and then poured into 5% aqueous sodium bicarbonatesolution; the product was extracted with several portions of chloroformand the extract was washed with water, dried over anhydrous sodiumsulfate and evaporated to dryness under reduced pressure at atemperature below 45 C. There was thus obtained 16ot-methyl-63-fluoro-2l-bromopregnan-3pg5u,l7a-triol-11,20-dione-5-acetate, whichwas used for the next step without further purification. A pure sampleof this compound was obtained by recrystallization fromchloroform-methanol at low temperature.

The above crude 16a-methyl 6p fluoro 21bromopregnan-3p,5a,17u-triol-11,20-dione S-acetate was mixed with 1.8 g.of sodium iodide, 1.5 g. of glacial acetic acid and 120 cc. of acetoneand the mixture was refluxed for 10 hours and then poured into water.The product was extracted several times with chloroform and the extractwas washed with water, dried over anhydrous sodium sulfate and thechloroform was evaporated. Recrystallization of the residue fromacetone-hexane afiorded 160cmethyl-6/3-fluoro-pregnan 3fi,5u,17a,21tetrol 11,20- dione 5,21-diacetate.

A stirred solution of 2 g. of the above compound in 100 cc. of aceticacid was treated little by little with a solution of 400 mg. of chromiumtrioxide in 10 cc. of water and 10 cc. of glacial acetic acid,maintaining the temperature below 15 C. After diluting with water,

the precipitate was filtered, washed with water, dried andrecrystallized from acetone-hexane. There was thus obtained 16a-methyl-G p-fluoro-pregnan-5 a, 1 7oz,21-tri0l-3,1 1, 20-trione5,21-diacetate.

A solution of 1.5 g. of the above compound in cc. of glacial acetic acidwas treated with 1.5 cc. of aqueous concentrated hydrochloric acid andthe mixture Was kept for 1 hour at room temperature. The product wasprecipitated by dilution with water and then filtered, washed withwater, dried and recrystallized from acetone-hexane. There was thusobtained 16a-methyl-6p-fluoro-cortisone 21-acetate.

1 g. of 16wmethyl-6,8-fluoro-cortisone ZI-acetate was dissolved in 100cc. of glacial acetic acid and a slow stream of dry hydrogen chloridewas introduced for 8 hours into the solution, maintaining thetemperature below 18 C. The mixture was poured into ice water and theprecipitate was collected, washed with water, dried and recrystallizedfrom acetone-hexane, thus yielding 16ocmethyl-6a-fluoro-cortisoneZl-acetate.

In another experiment the reaction with aqueous concentratedhydrochloric acid was omitted and 16a-methyl- 176fl-fluoro-pregnan-5a,17a,21-triol-3,11,20-trione 5,21 diacetate wasdirectly treated with dry hydrogen chloride in mixture with glacialacetic acid as described above, to produce16ot-IIlCthYI-Goa-flllOIOCOItlSOI1e 21-acetate.

EXAMPLE VIII A suspension of 1.8 g. of 16a-methyl-6fl-fiuoro-pregnan-3,8,5a,17a,21 tetrol 11,20 dione 5,21 diacetate, intermediate in themethod of the previous example, in 60 cc. of acetone was treated with an8 N solution of chromic acid obtained by dissolving 26.7 g. of chromiumtrioxide in 23 cc. of concentrated sulfuric acid and diluting to 100 cc.with water; the addition of the 8 N chromic acid was efiected dropwisein the course of minutes, with continuous stirring under an atmosphereof nitrogen and maintaining the temperature at around 10 C., until themixture showed a persistent brown-orange color. It was then stirred for5 minutes more, diluted with water and the precipitate formed wascollected, washed with water and recrystallized from methanol-water.There was thus obtained 16u-methyl-6fi-fiuoro-pregnan-5a,17a,2l-triol-3, 11,20-trione 5,21-diacetate, identical with the intermediatedescribed in Example VII.

EXAMPLE IX 5 g. of 16tit-methyl-6fl-fiuoro-pregnan-3/3,5a,17u-triol-11,20-dione S-acetate, intermediate in the method of Example VII, wastreated with chromic acid in accordance with the method of Example VII,to produce l6a-methyl- 6,8-fluoro-pregnan-5u,17u-diol-3,1 1,20-trioneS-acetate.

By following exactly the method described in Example VII, 3 g. of theabove compound was treated with aqueous concentrated hydrochloric acidin mixture with acetic acid, to give 16u-methyl-6fl-fluoroA-pregnen-17aol-3,11,20-trione, namely16a-methy1-6p-fluoro-2l-desoxycortisone; the steric configuration at C-6was inverted by treatment with dry hydrogen chloride in glacial aceticacid solution, to produce 16a-methyl-6u-fluoro-2l-desoxycortisone.

A cooled solution of 2 g. of 16zx-1T16thYl-6oc-fl1l0lO-21-desoxy-cortisone in cc. of tetrahydrofurane and 9 cc. of methanol wastreated under continuous stirring with 3 g. of calcium oxide and thenwith 3 g. of iodine. The stirring was continued at room temperatureuntil the solution turned pale yellow and then the mixture was pouredinto ice water containing 9 cc. of acetic acid and 1 g. of sodiumthiosulfate, stirred for 15 minutes and most of the liquid was separatedby decantation. The precipitate was filtered, washed with water anddried under vacuum. There was thus obtained16a-methyl-6u-fiuoro-2l-iodo- A -pregnen-17a-ol-3,11,20-trione in crudeform. The latter was mixed with 50 cc. of acetone and 6 g. of recentlyfused potassium acetate and refluxed for 8 hours. The mixture wasconcentrated to a small volume under reduced pressure, cooled, dilutedwith water and the product was extracted with ether. The extract waswashed with water, dried over anhydrous sodium sulfate and the ether wasevaporated. Crystallization of the residue from acetone-hexane yielded16a-methyl-6a-fluoro-cortisone 21- acetate.

EXAMPLE X A mixture of 5 g. of 16ot-methyl-6fl-fluoro-170:,20-oxido-pregnan-3fl,5a,20-triol-1l-one triacetate, intermediate in themethod of Example VII, and 500 cc. of a 1% solution of potassiumhydroxide in methanol was refluxed for 4 hours, neutralized with aceticacid and concentrated to a small volume under reduced pressure, theresidue was diluted with Water and the precipitate was collected, washedwith water, dried and recrystallized from acetonehexane. There was thusobtained the freel6a-methyl-6flfluoro-pregnan-3,(3,5a,l7a-triol-l1,20-dione.

This compound was then subjected to the reactions described in theprevious examples, exactly following the procedures therein described.By monobromination at C-Zl there Was obtained16a-methyl-6fi-fluoro-2l-bromopregnan-3B,5a,l7u-triol-11,20-dione; thesubsequent treatment with sodium iodide and potassium acetate furnished(via 16u-methyl-6B-fluoro-2l-iodo-pregnan 3fi,5oc,17octriol-11,20-dionewhich was not isolated) 16a-methyl-6B- fluoro pregnan 3fi,5ot,17a,21tetrol-11,20 dione 21- acetate; the step of oxidation then produced16a-methyl- 6B fiuoro pregnan 5a,17a,21-triol-3,11,20-trione 21-acetate; upon subsequent reaction with aqueous concentrated hydrochloricacid there was obtained 16u-methyl- 6fl-fiuoro cortisone 21-acetate,identical with the one described in Example VII.

EXAMPLE XI The oxidation of 16a-methyl-6B fiuoro pregnan-3/3,5a,17a-triol 11,20-dione of the previous example, in accordance with theprocedure of Example VII, afiorded 16a methyl 6fl-fluoropregnan-5a,17a-diol-3,11,20- trione; the latter was then converted into16a-methyl-6flfluoro-21-deoxycortisone or into 16oz methyl 6,8-fluoro-21-desoxycortisone, respectively, which were identical with theintermediates of Example IX; the reaction with hydrogen chloride wasconducted under the conditions therein described.

EXAMPLE XII A mixture of 3 g. of16a-methyl-6/8-fiuoro-2l-bromopregnan-3p,5a,17a-triol 11,20 dioneS-acetate, intermediate of Example VII, 7 g. of sodium iodide and 50 cc.of acetone was kept standing at room temperature for 24 hours (there canalso 'be used another solvent, such as ethanol). Then it was dilutedwith water and the product was extracted with ether, washed with sodiumthiosulfate solution until decoloration and then with water, dried overanhydrous sodium sulfate and the ether was evaporated, thus giving16ot-methyl-6fi-fiuoro 21 iodopregnan-3B,5u,l7a triol-11,20-dioneS-acetate in crude form. In another experiment the compound was obtainedin pure form by recrystallization from chloroform, at low temperature.

The crude iodo compound was then treated with potassium acetate inmixture with acetone, following the method of Example IX, to form16u-methyl-6fl-fiuoro- 3B,5a,17a,21-tetrol-11,20-dione 5,2 l-diacetate,identical to the intermediate described in Example VII; in anotherexperiment, the free16a-methyl-6B-fiuoro-2l-bromo-pregnan-35,5u,17a-triol-11,20-dione wasconverted by the same method into the intermediatel6a-methyl-6fl-fluoro-2liodo-pregnan-3,B,5a,l7u-triol-11,20-dione, whichwas in turn converted into 16a-methyl 6B-fiuoro-pregnan-3fi,5al7a,2l-tetro1-11,20-dione 21-acetate, identical with the compounddescribed in Example X.

EXAMPLE XIII 2 g. of 16a-methyl-6B-fluoro-2l-desoxycortisone,intermediate in the method of Example IX, was iodinated at C-21 by thereaction with calcium oxide and iodine, in accordance with the methoddescribed in Example IX, thus producing 16u-methyl-6 8-fiuoro-2l-iodo-A-pregnen- 17a-ol-3,11,20-trione; the latter was refluxed with potassiumacetate in mixture with acetone, as described in Example IX, to furnish16u-methyl-6fl-fluoro-cortisone 21- acetate.

EXAMPLE XIV By means of the reaction already described in the literatureof A -pregnadien-3B-ol-20-one with methyl magnesium bromide, preferablyfollowed by chromatography and/or purification by means of Girard Treagent, there was obtained l6a-methyl-A -pregnen-318-01-20 one (M.P.183-185" C.), which was acetylated to its 3-acetate by reaction withacetic anhydride in pyridine solution.

A solution of 5 g. of l6a-methyl-A -pregnen-3fiol-20- one acetate (M.P.177 C.) in cc. of chloroform was treated with an ether solution ofpermonophthalic acid containing 1.5 molar equivalents of the reagent;the mixture was allowed to react at room temperature for 16 hours,although other experiments showed that the epoxidation is almostcomplete after a shorter period (-6 hours). The mixture was diluted withwater and the organic layer was washed with water, then with 5% aqueoussodium bicarbonate solution and finally again with water, dried oversodium sulfate and evaporated to dryness. The residue waschromatographed on a column of neutral alumina, first eluting16u-methyl-5fl,6,8-oxidopregnan-35-o1-20-one acetate and then16a-rnethyl-5a,6:xoxido-pregnan-3fl-ol-20-one acetate, which waspurified by recrystallization from acetone-hexane (M.P. 161163 C.). Inother experiments the crude epoxidation product was purified bycrystallization, without chromatography, thus alfording16a-methyl-5a,6a-oxido-pregnan-3fi-ol-ZO- one acetate with M.P. l58160C., also sufficiently pure to be used for the transformation of the nextstep.

A solution of 3 g. of l6a-methyl-5u,6u-oxido-pregnan- 3fl-ol-20-oneacetate (M.P. l6l163 C.) in 300 cc. of a mixture of equal parts of etherand benzene was mixed with 3 cc. of boron trifluoride etherate and themixture was allowed to react at room temperature for 24 hours. Thesolution was then washed with 5% sodium bicarbonate solution and water,dried over anhydrous sodium sulfate, evaporated to dryness and theresidue was purified by chromatography on neutral alumina. There wasthus obtained 16u-methyl-6/3fiuoro-pregnan-3,8,5a diol- -one 3-acetate;M.P. 261-263 C.

A mixture of 8 g. of the above compound, 3.6 g. of ptoluenesulfonic acidand 400 cc. of acetic anhydride was subjected to a slow distillation for48 hours, collecting 320 cc. of distillate. The residue was cooled,poured into ice water and the product was extracted with ether, washedwith 5% aqueous sodium carbonate solution and water, dried overanhydrous sodium sulfate and the ether was evaporated. The oily residueconsisted of 16a-methyl-6/3- used for the next step without furtherpurification.

A mixture of 4 g. of the above crude compound and 160 cc. of a benzenesolution of perbenzoic acid containing 1.2 equivalents of the reagentwas kept at room temperature for 72 hours and diluted with water; theorganic layer was separated, washed with aqueous sodium bicarbonatesolution and water, dried over anhydrous sodium sulfate and evaporatedto dryness. The residue consisted of loot-methyl 6Bfiuoro-17,20-oxidopregnan-3 9,5a,20-triol triacetate. A sample waspurified by recrystallization from acetone-hexane.

The above crude compound was treated with 2 It. of a 0.5 N solution ofsodium hydroxide in 50% aqueous methanol, kept at room temperature for 1hour, acidified with acetic and concentrated to a small volume underreduced pressure; after diluting with ice water the precipitate formedwas collected, washed with a little cold Water, dried and recrystallizedfrom methanol-acetone. There was thus obtained l6a-methyl 6Bfiuoro-pregnan- 3/3,5a,17o-tIiOl-20OH6 5-acetate, melting point 2142l6C., [a]

A solution of 3 g. of the latter substance in 150 cc. of dioxane wastreated dropwise, with stirring at room temperature, with a solution of1.2 g. of bromine in 70 cc. of dioxane. After 5 minutes the solution waspoured into 10% aqueous sodium bicarbonate solution, the product wasextracted several times with chloroform and the extract was washed withwater, dried over anhydrous sodium sulfate and evaporated to drynessunder reduced pressure in a bath at a temperature below C. Byrecrystallization of a sample of the residue there was obtainedl6a-methyl 6;? fluoro-21-bromo-pregnan-3,8,5a,l7a-triol-20-one-S-acetate in pure form.

A mixture of 3 g. of the above crude 16cc methyl- 6B-fluoro 21 bromopregnan-3fi,5rx,l7a-triol-20-one- 5-acetate, 120 cc. of anhydrousacetone, 3.9 g. of anhydrous potassium acetate and 1.5 cc. of glacialacetic acid was refluxed for 9 hours. The suspension was then pouredinto water, extracted several times with chloroform and the extract waswashed with water, dried over anhydrous sodium sulfate and evaporated todryness. Crystallization of the residue from acetone hexane yielded16a-methyl 6/3 fluoro pregnan-3,8,5a,l7a,2ltetrol-ZO-one 5,21-diacetatemelting point 198-200 C., dD

A suspension of 0 mg. of the above compound in 30 cc. of acetonerecently distilled over potassium permanganate was treated dropwiseunder stirring with 22 cc. of an 8 N solution of chromic acid obtainedby dissolving 26.7 g. of chromium trioxide in 23 cc. of concentratedsulfuric acid and diluting to cc. The addition was carried out at atemperature between 10 and 15 C. and under an atmosphere of nitrogen.The mixture was stirred for 5 minutes further and then diluted withwater. The precipitate was collected by filtration, washed with waterand recrystallized from methanolwater, thus yielding 16a-methyl 6pfluoro-pregnan-Sa, 17a-2l-triol 3,20 dione 5,2l-diacetate, melting point22s-230 C., e1 +5".

A slow stream of dry hydrogen chloride was introduced for 2 hours into asolution of the above compound in 50 cc. of glacial acetic acid,maintaining the temperature below 15 C. After pouring into ice water,the precipitate formed was collected, washed with water, dried andrecrystallized from acetone-hexane. There was thus obtained l6a-methyl60c fluoro-M-pregnan 1704,21- diol 3,20 dione-acetate melting pointl96l98 C., [061D EXAMPLE XV A mixture of 3 g. of l6a-methyl 6Bfluoro-2l-bromopregnan-3B,5a,l7a triol 20 one 5-acetate, 7 g. of sodiumiodide and 50 cc. of acetone (ethanol can also be used) was allowed toreact at room temperature for 24 hours, diluted with water and extractedwith ether; the extract was washed with aqueous sodium thiosulfatesolution and the solvent as removed under reduced pressure in a bathbelow 35 C., thus leaving as a residue l6ix-methyl 6B fluoro 21iodo-pregnan-3fi,5u,l7a triol-ZO-one 5 acetate in crude form.

The above crude compound was mixed with 60 cc. of acetone and 8 g. ofrecently fused potassium acetate and the mixture was refluxed for 8hours, concentrated to a small volume and diluted with ether; theproduct was extracted with ether, washed with water, dried overanhydrous sodium sulfate and concentrated until crystallization started.After cooling, the crystals ere collected by filtration andrecrystallized from methanol-water, thus furnishing 16a methyl 6Bfluoro-pregnan-3B,5u,l7a ZI-tetrol 20 one 5,21-diacetate, identical withthe intermediate of the previous example.

EXAMPLE XVI To a cooled solution of 2 g. of 16a-methyl 65fluoropregnan-3/3,5a,17a triol-2 0-one-5-acetate in 15 cc. oftetrahydrofurane and 9 cc. of methanol there was added under continuousstirring and in small portion 3 g. of pure calcium oxide followed by 3g. of iodine. The stirring was continued at room temperature until thesolution turned pale yellow and then it was poured into ice watercontaining 1 g. of sodium thiosulfate and stirred for 15 minutes more.The solution was decanted and the precipitate was collected, thus givingl6u-methyl 65 fluoro-Zl-iodo pregnan-3l3,5a,l7zt-triol-20-one S-acetate,identical with the intermediate of the previous example.

EXAMPLE XVII In accordance with method described in Example XIV for theoxidation of l6u-methyl 6,8 fluoro pregnan- 3l3,5u,l7a,2l-tetrol-20-one5, 21 diacetate, there was treated 5 g. of 16a-methyl 6,8 fluoropregnan-3fl,5a, 17oc-t1l01 20 one S-acetate (intermediate in ExampleXIV) with 8 N chromic acid. There was thus obtained 16a-methyl 6/3fiuoro pregnan-Sa,l7a-diol-3,20-dione S-acetate.

A solution of 3 g. of the above compound in glacial acetic acid wastreated with dry hydrogen chloride for 4 hours at a temperature around15 C. and then poured into ice water. The precipitate was collected,washed with water, dried and recrystallized from acetone-hexane, thusaffording 16a methyl 6a fluoro-17ot-hydroxyprogesterone.

2 g. of the above compound in mixture with tetrahydrofurane and methanolwas treated with iodine and calcium oxide, exactly as described for thisreaction in Example XVI for the 2l-iodination of 160a methyl-65-fluoro-pregnan-35,5a,17a triol 20 one S-acetate. There was thus obtained16tx-methyl 6B fluoro 21- iodo-17ot-hydroxy-progesterone.

Upon subsequent acetolysis, by reaction with potassium acetate inmixture with acetone (see Example XV), there was obtained16a-methyl-6ot-fluoro-A pregnen-17a, 21-diol-3,20-dione 2l-acetate,identical with the final compound of Example XIV.

EXAMPLE XVIII A mixture of 10 g. of 16u-methyl-6a-fluoro-A pregnen-17u,21-diol-3, 20-dione 21-acetate and 300 cc. of 0.3% methanolic potassiumhydroxide solution was stirred for 1 hour at C. under an atmosphere ofnitrogen; it was then acidified with acetic acid, concentrated to asmall volume and precipitated with water, thus giving the free16ot-methyl-6a-fiuoro-A -pregnen- 17a,21-(ll0l-3,20-Cll01'16 in crudeform, which was collected by filtration, washed with water, dried andrecrystallized from acetone-hexane. By conventional esterification (acidanhydride pyridine) there was prepared the 21-propionate,21-cyclopentylpropionate and 2l-benzoate of this compound.

EXAMPLE XIX For the incubation with bovine suprarenal glands there wasprepared an aqueous medium as follows: there were mixed 425 cc. of a1.74% dipotassium hydrogen phosphate solution and 75 cc. of a 1.38%solution of sodium-dihydrogen phosphate (A); a mixture of 1 l. of 4.5%sodium chloride solution, 40 cc. of 5.75% potassium chloride solutionand 19.1% magnesium sulfate solution was diluted to l. (B); a solutionof 20.9 g. of fumaric acid and 14.4 g. of sodium hydroxide in l l. ofwater was diluted to 1.2 l. (C); then there were mixed 475 cc. of A,4.32 l. of B and 1.2 l. of C.

The fat was removed from the suprarenal glands obtained from recentlyslaughtered bovine, and the glands were then ground in a meat grinder; 3kg. of the resulting homogeneous mass was added to 6 l. of the aboveaqueous medium.

There was then added a solution of 3 g, of 16ozmethyl-6tx fiuoro-A-pregnen-17a,21 diol-3,2O dione in the minimum amount of propyleneglycol and the mixture was stirred for 3 hours at 2837 C.; 40 l. ofacetone was then added and the stirring was continued for 1 hour more atroom temperature.

The solid was removed by filtration and washed with two portions of l.of acetone; the combined filtrate and washings was evaporated to 5 1.under reduced pressure and at a temperature below C. The residue waswashed with 3 portions of 4 l. of hexane each and the hexane wasdiscarded. The reaction product was then extracted with several portionsof methylene chloride and the extract was washed with water, dried overanhydrous sodium sulfate and concentrated to 300 cc. under reducedpressure and taking care that the temperature did not rise over roomtemperature. The concentrated solution was transferred to a columncharged with a mixture of 90 g. of silica gel and 90 g. of celite andthe column was washed with a mixture of 3 l. of methylene chloride and100 of acetone and finally with a mixture of 1600 cc. of methylenechloride and 400 cc. of acetone, thus eluting with the latter solvents22 the 16ot-methyl-6ot-fiuoro-hydrocortisone, which was purified bycrystallization from acetone-hexane.

EXAMPLE XX A culture of Cunning/tamella bainz'eri ATCC 9244 was preparedby inoculating an aqueous medium containing 2% of peptone and 5% of cornsyrup with a vegetating growing culture of such fungus in the samemedium and then stirring at 28 C. for 24 hours.

To each liter of this culture there was added 30 cc. of a 1% solution of16ot-methyl-6a-fluoro-A -pregnen-17a, 21-diol-3,20-dione in methanol andthe mixture was stirred under aeration for 24 hours at 28 C. A total of3 g. of the steroid was incubated in this manner. The product was thenextracted with methylene chloride and the extract was washed with water,dried over anhydrous sodium sulfate and concentrated to a small volumeunder reduced pressure.

The combined concentrated extracts were absorbed in a column chargedwith a mixture of 60 g. of silica gel and 60 g. of celite previouslywashed with methylene chloride. The product was then eluted with amixture of methylene chloride and acetone (:20), the solvent wasevaporated and the residue was crystallized from acetone-hexane; therewas thus obtained 160t-I1lethy1-60C- fiuoro-hydrocortisone, identicalwith the one obtained in accordance with the method of the previousexample.

EXAMPLE XXI By following the procedure described in the previousexample, but substituting for the culture of Cunning- ,hamella baz nieria culture of Rhizopus nigricans ATCC 6227b, there was obtainedl6ot-methyl-6u-fiuoro-epihydrocortisone.

EXAMPLE XXII A mixture of 10 g. of 16wmethyl-6a-fiuoro hydrocortisone,obtained as described in Example XIX, 40 cc. of pyridine and 10 cc. ofacetic anhydride was kept overnight at room temperature and then pouredinto ice water. The precipitate was collected, washed with water, driedand recrystallized from acetone-hexane, thus yieldingl6nt-methyl-6a-fluoro-hydrocortisone Zl-acetate, M.P. 245248 C.; [aJ(chloroform); max. 236-8 my, log E 4.22.

A mixture of 10 g. of the above compound, 125 cc. of dimethylformamideand 7.5 cc. of pyridine was treated with 4.2 cc. of methanesulfonylchloride at 80 C. for half an hour, cooled and diluted with water. Theproduct was extracted with ethyl acetate and the extract was washed withwater, dried over anhydrous sodium sulfate and evaporated to dryness.Recrystallization of the residue from acetone-hexane afforded 16a methyl60a fluoro- A -pregnadien-17a,21-diol-3,20-dione 21-acetate.

A stirred mixture of 7.5 g. of the above compound, 75 cc. of puredioxane and 12 cc. of 0.4 N perchloric acid was treated in the course of1 hour with 4.2 g. of N-bromoacetamide, at room temperature and in thedark. The mixture was stirred in the dark for one hour further, treatedwith 10% sodium sulfite solution until the starchpotassium iodine paperno longer turned blue and then ice and cc. of chloroform were added. Theorganic layer was separated, washed with water, 5% sodium bicarbonatesolution and water, and evaporated to dryness under reduced pressure atroom temperature. Upon trituration of the residue with acetone andcooling, there was obtained16a-methyl-6a-fluoro-9ot-bromo-hydrocortisone 21-acetate.

A solution of 5 g. of the above compound in 10 cc. of dioxane was slowlytreated with a mixture of 1.6 g. of anhydrous potassium acetate and 20cc. of absolute ethanol, previously heated nearly to boiling. Themixture was refluxed for 45 minutes, cooled, diluted with 50 cc. of icewater and the precipitate formed collected, washed with water, anddried, thus producing 16a-methyl-6otfluoro 9/3,115 oxido A pregnen170:,21 diol 3,20- dione 2l-acetate.

In a polyethylene flask fitted with a magnetic stirrer there wasdissolved 5 g. of the above compound in 80 cc. of pure chloroform,cooled to C. and treated in the course of 20 minutes with 6.8 g. ofanhydrous hydrogen fluoride, with stirring and maintaining thetemperature at 0 C. The mixture was stirred for 2 hours longer and thenneutralized by the cautious addition of aqueous sodium bicarbonatesolution. The mixture was transferred to a separatory funnel, theorganic layer was separated, washed with water and concentrated underreduced pressure until an abundant precipitate separated, which wascollected. It was redissolved in 20 cc. of hot ethyl acetate, filteredfrom some insoluble material, concentrated and cooled, thus yielding16ot-Il'l6thYl-6OL,90t-dlfluoro-hydrocortisone 21-acetate.

A mixture of 1 g. of the above compound, 50 cc. of tbutanol, 200 mg. ofselenium dioxide and a few drops of pyridine was refluxed under anatmosphere of nitrogen for 48 hours and then filtered through celite.The solution was evaporated to dryness under reduced pressure and theresidue was dissolved in acetone, treated with decolorizing charcoal andrefluxed for 1 hour. After filtration, the solution was evaporated todryness and the residue of the crude product was purified bychromatography on neutral alumina, thus producing16ot-methyl-6a,9a-difiuoro-prednisolone 21-acetate.

EXAMPLE XXIII A solution of 4 g. of 16a methyl 6oz fluoro- 9B,l1;8 oxidoA pregnene 17o,21 diol 3,20 dione 2l-acetate, prepared in accordancewith the method of the previous example, in 40 cc. of pure chloroformwas cooled to 0 C. and slowly treated under stirring with a N solutionof dry hydrogen chloride in chloroform. The mixture was stirred for 1hour at 0 0, di luted with water and the organic layer was washed withwater, 5% sodium carbonate solution and again with water, dried overanhydrous sodium sulfate and the chloroform was removed.Recrystallization of the residue from acetone-hexane furnished16tit-methyl-6a-fluoro-9a-chlorohydrocortisone 21-acetate.

EXAMPLE XXIV 3 g. of 160: methyl 60c fluoro epi hydrocortisone, obtainedas described in Example XXI, was selectively acetylated at C-2l byreaction with 1 molar equivalent of acetic anhydride in pyridinesolution at 0 C.

Upon subsequent treatment with methanesulfonyl chlo- I ride, inaccordance with the method of Example XXII, there was obtained16a-methyl-6a-fluoro-A -pregnadien-17u,21-diol-3,20-dione 21-acetate,identical with the intermediate mentioned in such example.

EXAMPLE XXV By applying the method of dehydrogenation with seleniumdioxide described in Example XXII, g. of 160tmethyl 60c fluoro A pregnen170:,21 diol 3,20- dione 21-acetate was converted intol6a-I116'thYl-6wfill0l0- A pregnadien 170:,21 diol 3,20 dione 21acetate. By hydrolysis with potassium hydroxide, in accordance withExample XIX, there was then obtained the free 16ccmethyl 60c fluoro Apregnadien 1706,21 diol- 3,20-dione.

1 g. of the above compound was incubated with bovine suprarenal glands,in accordance with the procedure described in Example XIX, to producel6a-methyl-6afluoro-prednisolone.

1 g. of 1600 methyl 60c fluoro A prednadien- 170:,2l-dl0l-3,20-dl0l16was incubated with Cunninghamella bainieri ATCC 9244, in accordance withExample XX, to form 16a-methyl-6a-fiuoro-prednisolone.

By incubation with Rhizopus nigricans ATCC 6227b, in accordance withExample XXI, 1 g. of l6oc-m6thyl-6oc 24 fluoro A pregnadien l7oc,2l diol3,20 dione was converted into 16or-methyl-6a-flu0ro-epi-prednisolone.

By selective acetylation at C-21, using in the case of 16a methyl 6ozfluoro epi prednisolone only 1 molar equivalent of acetic anhydride, atlow temperature and in pyridine solution, there were obtained the 21-acetates of 16a-methyl-6ot-fluoro-prednisolone and of 160C-methyl-6a-fluoro-epi-prednisolone, respectively.

Upon subsequent reaction with mesyl chloride, in accordance with ExampleXXII, both of the above com pounds were converted into the same product,namely l6wmethyl-6a-fiuoro Amigul) pregnatrien 1711,21- diol-3,20-dione2l-acetate. By then applying the reactions described in Examples XXIIand XXIII, there were obtained the 21-acetates of16a-methyl-6a-fluoro-9a-bromoprednisolone, of 160a methyl 60 fluoro9,8,11,8- oxido A pregnadien 1704,21 diol 3,20 dione, of 1600 methyl6rx,9er difluoro prednisolone and of1dot-methyl-6a-fiuoro-9a-chloro-prednisolone.

EXAMPLE XXVI A mixture of 5 g. of l6or-methyl-6u-fluoro-acetate,described in Example XXII, and 100 cc. of acetic acid was treated with asolution of 1 g. of chromium trioxide in 20 cc. of acetic acid, at 15C., with stirring and for 2 hours; the mixture was then diluted withwater and the precipitate was collected, washed with water, dried andrecrystallized from acetone-hexane, thus yielding160cmethyl-6a-fiuoro-cortisone 21-acetate.

By dehydrogenation of 3 g. of the above compound with selenium dioxide,in accordance with the method described in Example XXII, there wasobtained 16a-methyl- Goa-fitlOIO-PIEClHlSOllB 21-acetate.

A solution of 2 g. of the above compound in methanol was treated withpotassium hydroxide, in accordance with the method of hydrolysisdescribed in Example XIX, to

give the free 16rx-methyl-9a-fluoro-prednisone.

A mixture of 1 g. of the above compound, 10 cc. of pyridine and 3 g. ofcyclopentylpropionic acid anhydride was kept overnight at roomtemperature, poured into water, heated for 1 hour on the steam bath,cooled and extracted with methylene chloride; the extract was washedwith dilute hydrochloric acid, water, saturated sodium bicarbonatesolution and again with water, dried over anhydrous sodium sulfate andthe solvent was evaporated. Recrystallization of the residue fromacetone-hexane produced 16a-methyl-6a-fluoro-pre-dnisone21-cyclopentylpropionate.

EXAMPLE XXVII By following the method described in the previous example,16a methyl 60,9oc difluoro hydrocortisone Zl-acetate was oxidized to16a-methyl-6a,9a-difiuoro-cortisone 21-acetate and the latter wasdehydrogenated to form 16or-methyl-6a,9a-difluoro-prednisone 21 acetate,which was then hydrolyzed to the free 16tZ-methyl-6OL,9d'difluoro-prednisone; by treatment of 1 g. of the latter with 2 cc. ofpropionic anhydride in 10 cc. of pyridine for 2 hours at roomtemperature, followed by precipitation with water and purification bycrystallization from acetonehexane, there was obtained16a-methyl-6u,9u-difluoro-prednisone 2l-propionate.

We claim:

1. A compound of the following formula:

(llmo R o 0 25 wherein R is selected from the group consisting ofhydrogen and a hydrocarbon carboxylic acyl group of less than 12 carbonatoms.

2. 160a methyl 60c fluoro A pregnen 170c,21- diol-3,20-dione.

3. The 21-mono hydrocarbon carboxylic acid esters of 5 less than 12carbon atoms of 16u-methyl-6a-fiuoro-A pregnan-17a,21-diol-3,20-dione.

4. A compound of the following formula:

OHzOR 5. 16a methyl 6oz fluoro A pregnadien-17a,21- diol-3,20'-dione.

6. The hydrocarbon carboxylic acid esters of less than 12 carbon atomsof 16tx-methyl-6u-fiuoro-A -pregnadien- 17a,21-diO1-3,20-di0116.

7. 160a methyl 6a fluoro A pregnen 170:,21- diol-3,20-dione 21-acetate.

8. 160a methyl 6a fluoro A pregnadien-17a,2ldiol-3,20-dione ZI-acetate.

References Cited UNITED STATES PATENTS 2,838,497 6/1958 Spero et al.260239.55 2,838,498 6/1958 Magerlein et a1, 260-239.55 2,838,499 6/1958Spero et al 260239.55 2,841,600 7/1958 Hogg et al. 260397.45

OTHER REFERENCES Arth et al.: J. Am. Chem. Soc., vol. 80, pp. 3160-62(1958).

ELBERT L. ROBERTS, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 538,131

Dated November 3, 1970 nt )HQward J. Ringold. Carl D-lerassi, John A.Edwards It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

The first 3 formulas in Columns 3 and 4 should appear as follows:

sodium borohydride semicarbazide then pyruvic acid a etate and aceticacid CH OR C=N-NH INH 0 --0H 0 HIT-N UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent No. 3,538 131 Dated November 3, 1970Inventor(s) Howard J. Ringold et al. Page 2- It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

In Column 8, the second formula should appear as follows:

Column 18, line 20, "fluoro-2l-deoxycortisone" should befluoro-Zl-desoxycortisone Column 19, line 50, after 'acetic" insert acidColumn 20, line 37, "as" should be was Column 20, line 47, "ere" shouldbe were Column 24, line 22, after "6CL-fluoro-" and before "acetate,insert hydrocortisone Column 25, line 8 (Claim 3) "pregnan-" should bepregnen Signed and sealed this 1 8th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,J'R. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents FORM PO-IOSO (IO-69] nrnnnnnn 1m

1. A COMPOUND OF THE FOLLOWING FORMULA: